This invention relates to a refrigerator testing assembly, and more particularly to an assembly for positioning transducers in thermal contact with the end of a refrigerator cold tip.
For monitoring and testing the cooling capacity of a cryogenic refrigerator, it is common practice to attach a resistance heat load and temperature sensor to the cold tip at the end of a cold finger of the refrigerator. A closefitting vacuum chamber is then placed over the cold tip and operation of the refrigerator is monitored. Usually, the heating and sensing transducers are mounted on a copper adapter which is soldered, glued or clamped onto the end of the cold tip. The walls of the cold finger are paper thin; and because removal of the adapter from the cold tip could damage or mar the finger, it has not been feasible to thus monitor the cooling capacity of all units before sale. Rather, quality control has been based on the testing of only selected ones of the refrigerators.
Another problem encountered in prior methods of attaching transducer supporting adapters to cold tips has been that, to test under a wide range of conditions, limited range transducers must be replaced at various steps of the testing procedure.
The difficulties encountered in removing and replacing transducer adapters are complicated by the fact that the transducers and their connecting electrical leads are extremely delicate. For example, the leads are commonly hair-like fine gold wire.
An object of this invention is to provide a means for removably mounting a transducer assembly in good thermal contact to the end of a cold tip.
A further object of this invention is to provide a transducer assembly whereby removal of the assembly can be made without damaging the sensitive transducers and without damaging or marring the cold tip of the refrigerator.